Web printing presses at their output end are normally coupled to a "sheeter" device for cutting a printed product from a continuous web into brochures, pamphlets, etc., of a desired length (units). The sheeter may comprise one or more sets of cooperating knife and anvil rollers between which the web is fed. Knives are disposed longitudinally on one or both of the rollers, extending radially outward from the circumference of the roller and arranged to come into slight contact, or "kiss," with the opposing roller. The knives are spaced apart around the circumference of the roller in a manner such as to make cuts at desired locations with scrap pieces or "chips" being transversely cut between the end of one unit and the beginning of the next unit. These transversely cut chips must be removed from the cutting area and disposed of as waste. Removal of chips from such devices has been carried out by providing pins protruding from a roller of a rotary cutter, or sheeter, the pins being arranged to impale the chips as they are being cut. As the roller rotates, it carries the pins with impaled chips so they can be released and conveyed to a container for disposal.
Various arrangements for removing pin-impaled chips from cutter rollers are disclosed in prior art patents, exemplified by U.S. Pat. No. 4,846,030, issued Jul. 11, 1989, to McMahon et al., which discloses apparatus wherein impaled chips are removed in an arcuate path, scraped off onto a moving belt, and conveyed to a receptacle. U.S. Pat. No. 3,893,359, issued Jul. 8, 1975, to Gregoire, provides for removing impaled chips from a roller by use of spaced-apart fingers adjacent to the back side of the roller, the fingers stripping the chips from the pins as they pass between the fingers. Chip removal devices that rely on mechanical parts such as fingers, combs, or the like for physical removal present disadvantages in that precise adjustment and synchronization are required for their operation, and they tend to be expensive to manufacture and install. They also may interfere with access to other parts of the overall system.
Air jets or high pressure gas streams for removal of scrap cut from webs of material are disclosed in several prior patents. U.S. Pat. No. 3,252,366, issued May 24, 1966, to Karr, shows air jets for directing high velocity air to the cutting area of a slitter device for trimming a strip from the edge of a traveling web. U.S. Pat. No. 3,670,612, issued Jun. 20, 1972, to Johnson et al., discloses use of air under pressure to blow away scrap pieces generated in cutting cards from a web. While these and other patents show various ways of applying air streams for the purpose of removing scrap material generated by a rotary cutter, none of them discloses or suggests the present invention which includes using a flow channel spaced along the length of the chip-carrying roller and having defined features by means of which a high velocity is imparted to an air stream being drawn through the flow channel.